To join functional elements, in particular cams, to a shaft, in particular to a camshaft tube, the hubs or cut-outs in the individual functional elements must be aligned with the axis of the shaft. If one or a plurality of functional elements is to be joined in one go by introducing the shaft, all the functional elements must be aligned accordingly.
DE 10 2008 064 194 A1 discloses a device suitable for this, for positioning a plurality of functional elements, in particular cams, having a cut-out for a shaft in a predefined angle position on the shaft, the device having a plurality of holders each intended for one functional element. The holders can be positioned in such a manner that the cut-outs in the functional elements lie substantially in a common straight line.
When a cam or a plurality of cams at once are mounted on a shaft, the cam to be mounted is usually grasped with a gripper or held in a holder and heated, and then the camshaft tube or generally a shaft is introduced until the at least one cam has reached its end position. So that the camshaft tube or generally the shaft can be supported when being passed through the cam or generally the functional element, a tailstock having a tailstock tip first passes through the functional element from the opposite side and picks up the shaft or specifically the camshaft tube. Then the tailstock passes back through the cut-outs in the functional elements together with the shaft. The functional elements or specifically the cams are already positioned sufficiently precisely for at least the tailstock tip, which has a smaller diameter than the shaft, to pass through the cut-outs without problems. Incorrectly positioned functional elements can thereby be aligned at least roughly in advance with the tailstock head. The prior correction of coaxial errors is then continued while the shaft is passed through by means of the insertion bevel on the shaft tube and the functional elements are thereby threaded onto the shaft.
While the shaft is passing through, however, the functional element to be threaded on can come into contact with the shaft in part-regions of the hub of the functional element and brief fretting or chip formation can occur as a result. In addition, there can be a risk that the functional element is misaligned in the gripper itself and cools in this misaligned position when in its end position, resulting in a positional defect.